You'd think insurers would want their clients to keep as fit as possible. But, as Paul Slade discovers, many sports can leave your premiums and cover looking less than healthy.

Hang-gliders, potholers, mountaineers and polo players are just a few of the people who may find their weekend sport creates problems with their life and health insurance.

One area likely to be hit is PHI, or permanent health insurance, which provides policyholders with an income when unable to work through illness or accident. Some insurers, such as Abbey Life and Eagle Star, will refuse to pay out if the injury arose through any activity on their list of dangerous sports. Others will accept the risk, but charge a higher premium. A few will look in detail at the circumstances involved and may make no extra charge.

Colin Young of Unum, a specialist health insurer, says: "What we're looking for is people who are pursuing these sports in a regulated environment and following safety procedures. If it's motorised hang-gliding, we'd want to know they've got a private pilot's licence. If it's parachuting, we'd want to see they're doing it as part of a club."

The individual's level of experience also counts for a lot. In cases like this, Mr Young says, no extra loading may be needed. Where loadings are deemed necessary, they could add anything from 25 per cent to 100 per cent to the size of the premiums. The same principle applies to life insurance and private medical cover although, in the case of life insurance, you are less likely to face exclusions than a simple hike in premiums.

Less hazardous sports, such as rugby or football, seldom trouble underwriters. You may find, however, that health insurance underwriters are tougher on sports such as rugby than their life insurance counterparts. This is because you have a higher chance of being injured on the rugby field than of dying there.

Application forms will ask you to specify any dangerous sports you may be involved in. Those admitting to daredevil hobbies get a second questionnaire asking for more details.

These forms are designed to flag up not only risky sports, but also any hazards involved in your work. Friends' Provident, for example, has one question on its form designed to uncover any applicants who may have forgotten to mention their work in bomb disposal.

It is important to complete them honestly. Admitting only to a little light golf when you spend every spare minute hot air ballooning could invalidate any claim you may later need to make. Independent financial adviser Amanda Davidson says: "I'm a great believer in putting everything down on the form. If you had your tonsils out at the age of two, put it down."

Ms Davidson's own passion is for scuba diving. But because she sticks to safe areas and relatively shallow dives, she has found no need to pay extra for her own insurance.

Mr Young recommends going back to your insurer or adviser to see if the experience you have gained in your chosen sport may qualify you for lower premiums. "We will reassess the case," he says.

Ms Davidson adds: "If I get a situation with a client where the insurer says they don't like a certain sport or they want to put an extra on the premium, I tend to argue the toss with the underwriters and negotiate. They will reduce loadings or take them off. So don't accept the first loading they come up with, or the first exclusion."